TAF without flag -nocat4ad on MacOS

[mjlosch]

Since PR #208 the flag -fixed is passed to TAF as part of TAF_EXTRA if -nocat4ad is specified, because "to get the *.flowdir processed correctly", because the flow-files with non-standard suffix .flow were treated as free-format by default.
This seems to be the problem here, too, as with MacOS the fixed format f77 files have the extension .for because the MacOS filesystem is case insensitive. All non-standard (.f) files with suffix .for are interpreted as free form leading to multiple errors.

I suggest to change

MITgcm/tools/genmake2

Line 1830 in 4d72283

if test $CAT_SRC_FOR_TAF = 0 ; then TAF_EXTRA="${TAF_EXTRA} -fixed" ; fi

to

TAF_EXTRA="${TAF_EXTRA} -fixed"

for all cases. There are potential conflicts with #709, but that is not moving and we can sort that out later. In fact, #709 aims to combine fixed and free format file and since TAF-version 5.8.0 this is possible.